The control of unwanted vegetation is a continually important effort as it is needed for reducing health problems, such as allergies, the removal of poisonous/noxious weeds, increasing crop productivity, as well as improving the general aesthetics around the home. Unwanted vegetation can be controlled using herbicides that are either selective or non-selective. An example of a commonly used non-selective herbicide is glyphosate, marketed under the trade name Roundup®, among others, which kills all vegetation it contacts. Alternatively, a selective herbicide only affects the undesired plant species while leaving the desired species relatively unaffected. An example of a well-known auxin-type selective herbicide is 2,4-dichlorophenoxyacetic acid (also known as “2,4-D”), which is commonly used for the removal of broadleaf weeds growing in grass and turf.
There are a variety of selective herbicides that are available on the market for the selective control of grass and broadleaf weeds growing in a variety of crops. The majority of these herbicides are synthetic compounds, with some herbicides raising concerns in recent years as to their safety to humans and the environment in general. Within the context of postemergent broadleaf weed control in grass, auxin-type herbicides are commonly used. There are four main families of synthetic auxin-type herbicides available on the market, including: the phenoxyacetic acid or phenoxyalkanoic acid family (e.g. 2,4-D), the benzoic acid family (e.g. dicamba), the pyridine carboxylic acid or picolinic acid family (e.g. triclopyr), and the quinolinecarboxylic acid family (e.g. quinclorac). These auxin-type herbicides are systemic compounds that have activity against a number of broadleaf weeds including perennial species. A number of registered products exist with these compounds, some using the individual compounds alone while others have two or three combined together (e.g., Killex® contains 2,4-D, mecoprop and dicamba).
A drawback of the synthetic auxin-type herbicides is their slow speed of activity. Often herbicidal activity is not seen for several weeks after application. Moreover, the products that are available for use by homeowners often do not result in adequate weed control with one application, resulting in the need for additional applications in order to achieve acceptable weed control.
Accordingly, there is a need in the art for novel methods and compositions for the improvement and enhancement of selective auxin-type herbicides that will benefit both consumers and the environment.